Homelessness among adolescents is a significant problem, with youth that become chronically homeless also being those at greatest risk for acquiring HIV. When youth are newly homeless, there is a significant opportunity to intervene to reduce chronic homelessness and, thus, risk for HIV. The rationale for this window of opportunity is based on results from an existing project that has found: family conflicts to be the predominant precipitant for leaving home; 68% of newly homeless youth return home within 3 months, but this reunification is unstable, with longer runaway episodes over time; contact with parents being a significant predictor of reunification; developing social networks with peers that are substance abusers, homeless, and out of school predicts remaining homeless. A 5-session family intervention for newly homeless youth, Parents and Adolescents Collaborating Together (PACT), is proposed to improve residential stability and the quality of residential life, reduce the number of runaway episodes, as well as reduce HIV-related sexual and substance use risk acts. PACT will reframe the runaway episode and improve family functioning by redefining the family conflict, increasing problem-solving skills, gaining role clarity, and promoting positive family interactions. The project will proceed in two phases. Phase 1 will serve to pilot and finalize all instruments, intervention procedures, and to improve the standard care in all shelters to a routinely evaluating family reunification. In Phase 2, a randomized control trial will be conducted based on a group cross-over randomization design to test the efficacy of PACT for newly homeless youth aged 12-17 years and their parents. In four community-based agencies that provide short-term shelter, newly homeless youth (n--320) will be randomized to one of two conditions: 1) standard care (n =160); or 2) the PACT intervention (n = 160). PACT sessions will take place with the families in the intervention condition while youth are in the shelter and as they transition to a more stable living environment (e.g. back to the home). Youth's outcomes will be monitored at recruitment, 3, 6, 12, 18, and 24 months; parents will be assessed at recruitment, 3 (immediate post), 12 and 24 months to examine the efficacy of PACT on: sexual and substance use risk acts; residential stability, runaway episodes, and quality of residential life; family functioning; and generalization to youth's mental health, multiple problem behaviors, and school performance. [unreadable] [unreadable]